It depends on the jurisdiction. Patent infringement can be a criminal matter in Germany, for example. As far as I can see, this may also apply to non-commercial activity. (Not that there are many sustained activities conducted over the Internet German courts would consider non-commercial, a profit motive is usual not required.)
Patents aren't special in this regard in Germany. Copyright violations, trademark violations, and unauthorized disclosure of trade secrets are criminalized as well. So at least it's consistent.
